Add a new cache mode 'follow'

lib/cradle.js

@@ -26,7 +26,8 @@ cradle.options = {
     retries: 0,
     retryTimeout: 10e3,
     forceSave: true,
-    headers: {}
+    headers: {},
+    forceReconnect: false,
 };
 
 cradle.setup = function (settings) {
@@ -155,13 +156,14 @@ cradle.Connection.prototype.rawRequest = function (options, callback) {
                 options.query[k] = String(options.query[k]);
             }
         }
-        options.path += '?' + querystring.stringify(options.query);
+        options.uri = this._url(options.path + '?' + querystring.stringify(options.query));
+    }
+    else {
+        options.uri = this._url(options.path);
     }
 
     options.headers['Connection'] = options.headers['Connection'] || 'keep-alive';
     options.agent = this.agent;
-    options.uri = this._url(options.path);
-    delete options.path;
 
     return request(options, callback || function () { });
 };
@@ -214,6 +216,12 @@ cradle.Connection.prototype.request = function (options, callback) {
     return this.rawRequest(options, function _onResponse(err, res, body) {
         attempts++;
         if (err) {
+            if (self.options.forceReconnect && String(err.code).startsWith('ECONN')) {
+              return setTimeout(
+                  self.rawRequest.bind(self, options, _onResponse),
+                  self.options.retryTimeout
+              );
+            }
             if (self.options.retries &&
               (!options.method || options.method.toLowerCase() === 'get' || options.body) &&
               String(err.code).indexOf('ECONN') === 0 && attempts <= self.options.retries
@@ -253,8 +261,8 @@ cradle.Connection.prototype.request = function (options, callback) {
 //      We return an object with database functions,
 //      closing around the `name` argument.
 //
-cradle.Connection.prototype.database = function (name) {
-    return new cradle.Database(name, this)
+cradle.Connection.prototype.database = function (name, opts) {
+    return new cradle.Database(name, this, opts)
 };
 
 //

lib/cradle/database/changes.js

@@ -50,7 +50,21 @@ Database.prototype.changes = function (options, callback) {
 
         response.emit.apply(response, ['data'].concat(Array.prototype.slice.call(arguments)));
     });
-
+
+    var self = this;
+    // Keep a consistent object for return to the client, even if
+    // this feed is restarted due to error.
+    feed.on('error', function (err) {
+        if (feed.dead && options.follow !== false) {
+          console.error(self.name, 'ERROR: Cradle changes feed died, restarting', err.message || err);
+          setTimeout(function() {
+              console.error(self.name, 'RECOVERY: Restarting feed that died with', err.message || err);
+              feed.restart();
+              feed.emit('recover', err);
+          }, 1000);
+        }
+    });
+
     if (options.follow !== false) {
         feed.follow();
     }

lib/cradle/database/index.js

@@ -2,15 +2,60 @@ var querystring = require('querystring'),
     Args = require('vargs').Constructor,
     cradle = require('../../cradle');
 
-var Database = exports.Database = function (name, connection) {
+var Database = exports.Database = function (name, connection, opts) {
     this.connection = connection;
     this.name = encodeURIComponent(name);
-    this.cache = new (cradle.Cache)(connection.options);
+    this.opts = {...connection.options};
+    if (opts && opts.disableCache) {
+       this.opts.cache = false;
+       this.opts.cacheSize = 0;
+    }
+
+    // Workaround https://issues.apache.org/jira/browse/COUCHDB-1415 by default
+    this.workaroundBug1415 = true;
+
+    this.cache = new (cradle.Cache)(this.opts);
+    this.cacheFeed = null;
+    if (this.opts.cache === 'follow') {
+       var self = this;
+       this.exists(function(err, result) {
+           if (result === true)
+               self.configureCacheFeed();
+       });
+    }
+};
+
+Database.prototype.configureCacheFeed = function () {
+    if (this.cacheFeed) {
+        this.cacheFeed.stop();
+        this.cacheFeed = null;
+    }
+    // For any entry already in the cache, update it if it changes
+    // remotely.
+    if (this.opts.cache === 'follow') {
+        var self = this;
+        this.changes({descending: true, limit: 0}, function (err, list) {
+            var lastSeq = 0;
+            if (list && 'last_seq' in list)
+                lastSeq = list.last_seq;
+            self.cacheFeed = self.changes({ since: lastSeq, include_docs: true });
+            self.cacheFeed.on('change', function (change) {
+                var id = change["id"];
+                if (id && 'doc' in change && self.cache.has(id))
+                    self.cache.save(id, change["doc"]);
+            });
+        });
+    }
 };
 
 // A wrapper around `Connection.request`,
 // which prepends the database name.
 Database.prototype.query = function (options, callback) {
+
+    // XXX: Workaround https://issues.apache.org/jira/browse/COUCHDB-1415
+    if (options.body && options.method === 'POST' && this.workaroundBug1415)
+      options.body.$ts = Date.now();
+
     options.path = [this.name, options.path].filter(Boolean).join('/');
     return this.connection.request(options, callback);
 };
@@ -39,7 +84,11 @@ Database.prototype.info = function (callback) {
 };
 
 Database.prototype.create = function (callback) {
-    this.query({ method: 'PUT' }, callback);
+    var self = this;
+    this.query({ method: 'PUT' }, function () {
+        self.configureCacheFeed();
+        callback.apply(this, arguments);
+    });
 };
 
 // Destroys a database with 'DELETE'
@@ -48,12 +97,12 @@ Database.prototype.create = function (callback) {
 Database.prototype.destroy = function (callback) {
     if (arguments.length > 1) {
         throw new(Error)("destroy() doesn't take any additional arguments");
-    } 
-    
+    }
+
     this.query({
-        method: 'DELETE', 
-        path: '/', 
-    }, callback);    
+        method: 'DELETE',
+        path: '/',
+    }, callback);
 };
 
 //
@@ -62,4 +111,4 @@ Database.prototype.destroy = function (callback) {
 require('./attachments');
 require('./changes');
 require('./documents');
-require('./views');
+require('./views');